Viewable displays are well-known and can be implemented in many different technologies, e.g., cathode ray tubes (CRTs), liquid crystal displays (LCDs), and plasma displays. Displays present information from some electronic system in a format for viewing by human audiences. For example, displays are used for televisions, computer screens, airport monitors, and hand-held electronic devices such as pagers, cell phones, and personal organizers. Displays also find applications in the interior dashboard of automobiles to show road speed, engine revolutions per minute, fuel level, and engine monitoring and diagnostics. In more sophisticated applications, the dashboard display may present global positioning system (GPS) data in the form of maps, surrounding terrain, weather, and traveler's information and advisories.
Automobile owners and occupants often find the need or desire to put information on the exterior of the vehicles. The information is intended for those who need to know, or for those whom the occupants of the automobile would like to reach. For example, bumper stickers have been around for many years to make political statements, support favorite sport teams, demonstrate for or against causes, show allegiance to schools or organizations, tout child's academic performance, and generally to make a statement. License plate frames contain advertisements and statements about the occupants' hobbies, e.g., “I'd rather be golfing”. Taxis have billboards attached to the trunk or roof. Busses have advertisements on the side panels. Commercial transport trucks have caution signs, such as “Hazardous material” or “Oversized Load”. These type of fixed displays are pre-printed, affixed to a surface of the vehicle, and are not designed or intended to be readily changed or re-used. When the need or desire to make the statement has passed, then the message is removed and possibly replaced with another fixed message.
In another application, changeable vehicle displays can be found on buses and public transportation. A bus may have the next scheduled stop displayed on a front display, e.g., mounted interior against the windshield. The next-stop display is a separate stand-alone unit which is bolted to the roof of the bus. The bus displays are low-resolution, generally a light emitting diode (LED) matrix. At best, the bus display may contain a few letters indicating the next scheduled stop or present status, e.g., “Main St.”, or “University”, or “Out-of-Service”. Although the display can be changed, it typically requires some input from the driver. The driver may punch up “Main St.”, which will be displayed until the bus arrives at Main St. The driver then dials-in the next scheduled location with a push button or knob.
The difficulty in the fixed displays and selectable displays is the limited amount of information that is presented and the requirement to manually change the information content of the display. The driver must peal-off the bumper sticker, change out the sign or billboard, or press buttons to put up other information. Even displays that can be changed are low-resolution, convey very limited information, and the information remains fixed until it is manually changed.